Middle-Late Quaternary paleoclimate of northern margins of the Saharan-Arabian Desert: reconstruction from speleothems of Negev Desert, Israel
- Permanent Link:
- Middle-Late Quaternary paleoclimate of northern margins of the Saharan-Arabian Desert: reconstruction from speleothems of Negev Desert, Israel
- Series Title:
- Quaternary Science Reviews
- Vaks, Anton
- Publication Date:
- Subjects / Keywords:
- Negev Desert ( local )
Speleothems ( local )
U-Th Dating ( local )
Paleoclimate ( local )
Out Of Africa ( local )
- serial ( sobekcm )
- Speleothems in arid and hyper-arid areas of Negev Desert, Israel, are used in paleoclimate reconstruction of northern margins of Saharan-Arabian Desert, focused on the following objectives: 1) precise Uâ€“Th dating of the timing of speleothem growth as an indicator of periods of humid climate, i.e. positive effective precipitation; 2) the origin of rainfall using the speleothem Î´18O and changes in spatial pattern of speleothem deposition and speleothem thickness along a northâ€“south transect; 3) changes of vegetation cover based on speleothem Î´13C variations.
During the last 350 ka major humid periods, referred to herein as Negev Humid Periods (NHP), occurred in the central and southern Negev Desert at 350â€“310 ka (NHP-4), 310â€“290 ka (NHP-3), 220â€“190 ka (NHP-2), and 142â€“109 ka (NHP-1). NHP-4, NHP-2 and NHP-1 are interglacial events, whereas NHP-3 is associated with a glacial period. During NHP-1, 2 and 3 the thickness and volume of the speleothems decrease from the north to the south, and in the most southern part of the region a very thin flowstone layer formed during NHP-1, with no speleothem deposition occurring during NHP-2 and 3. These data imply that the Eastern Mediterranean Sea was the major source of the rainfall in northern and central Negev. More negative speleothem Î´18O values, relative to central parts of Israel (Soreq Cave) are attributed to Rayleigh distillation because of the increasing distance from the Mediterranean Sea. Speleothem deposition during the NHP-4 in the southern Negev was more intensive than in most of the central Negev, suggesting the prominence of the tropical rain source.
Decrease in speleothem Î´13C during NHP events indicates growth of the vegetation cover. Nevertheless, the ranges of Î´13C values show that the vegetation remained semi-desert C4 type throughout the NHPs, with an additional significant carbon fraction coming from the host rock and the atmosphere. These observations, together with small thickness of the speleothem layers, favor that NHP events consisted of clusters of
- Original Version:
- Quaternary Science Reviews, Vol. 29, no. 19-20 (2010-09-01).
- Source Institution:
- University of South Florida Library
- Holding Location:
- University of South Florida
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- This object is protected by copyright, and is made available here for research and educational purposes. Permission to reuse, publish, or reproduce the object beyond the bounds of Fair Use or other exemptions to copyright law must be obtained from the copyright holder.
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